Fondazione IRCCS Istituto Nazionale Neurologico C.Besta, Via Celoria 11, 20133, Milan, Italy.
Neurol Sci. 2011 Dec;32 Suppl 3:S311-6. doi: 10.1007/s10072-011-0692-3.
The Chiari malformation (CM) is a syndrome embodied in heterogeneous groups of malformations, spanning from the more benign and known, the CM1, to more complex syndromes such as the rare association with the tethered cord, as spinal lipomas, and the CM2, associated to open spina bifida. The clinical picture may be well expressed and detected at birth or even during intrauterine life, as for CM2, but in the other cases they may run a rather subtle clinical course. The diagnosis of these syndromes is driven by clinical examination and MRI, and it usually requires a multidisciplinary approach in order to plan the therapeutic strategies, such as surgery. Among the diagnostic investigations, the imaging techniques represent the most useful, for their capabilities to detect subclinical lesions, such as syringomyielia and lipoma; the urological investigation is useful to evaluate the urogenital dysfunctions. The neurophysiological investigations represent a non invasive diagnostic procedure to investigate the peripheral nerve, the spinal cord, the brainstem functionalities and more higher brain functions; the nerve conduction studies and the cranial reflexes, the brainstem (BAEP) and the somatosensory (SEPs) evoked potentials (EPs), alone or in combination, can be used for the diagnosis, follow-up and intraoperative monitoring. The most useful diagnostic tools in CM1 are likely represented by the brainstem auditory evoked potentials (BAEPs) and the blink-reflex (BR), while the usefulness of SEPs is still doubtful and debated; in CM2 and tethered cord the neurophysiological techniques can be combined in different ways in order to make a functional balance and to answer specific questions. BAEPs and BR can be useful to investigate the brain stem functionality and SEP to evaluate whether the ascending sensory pathway to the cortex can be hampered at some level; the visual EPs are particularly useful to evaluate the integrity of posterior visual pathway and visual cortex in the case of associated hydrocephalus. In the tethered cord, both nerve conduction study and somatosensory evoked potentials (SEPs) are useful to evaluate motor and sensory dysfunction of the lombosacral roots and nerves and spinal cord for their capability to detect subclinical impairment of conduction along the sensory and motor pathway. Finally, last but not the least, the neurophysiological techniques are remarkably useful during surgery; the intraoperative monitoring (IOM) by means of electromyography and direct nerve stimulation and recordings are able to detect early nerve damage, minimize nerve lesions and optimise the surgical techniques. In the operated children with incomplete removal of lipoma and/or persistent tethering, the recordings of SEP and BAEP are useful to demonstrate a conduction deterioration along the ascending sensory pathway due to increasing tethering of the spinal cord due to somatic growth.
Chiari 畸形（CM）是一组异质性畸形综合征，包括从良性和已知的 CM1 到更复杂的综合征，如罕见的脊髓栓系伴脊髓脂肪瘤和 CM2，伴开放性脊柱裂。临床表现可在出生时或甚至在宫内生活中明显表达和检测，如 CM2，但在其他情况下，它们可能表现出相当微妙的临床过程。这些综合征的诊断由临床检查和 MRI 驱动，通常需要多学科方法来规划治疗策略，如手术。在诊断性检查中，影像学技术是最有用的，因为它们能够检测亚临床病变，如脊髓空洞症和脂肪瘤；泌尿科检查有助于评估泌尿生殖功能障碍。神经生理学检查是一种非侵入性诊断程序，用于检查周围神经、脊髓、脑干功能和更高的大脑功能；神经传导研究和颅反射、脑干（BAEP）和体感（SEP）诱发电位（EPs），单独或组合使用，可用于诊断、随访和术中监测。CM1 中最有用的诊断工具可能是脑干听觉诱发电位（BAEPs）和眨眼反射（BR），而 SEP 的有用性仍存在争议；在 CM2 和脊髓栓系中，神经生理学技术可以以不同的方式组合，以达到功能平衡并回答特定问题。BAEPs 和 BR 可用于研究脑干功能，SEP 可用于评估上行感觉通路到皮质是否在某个水平受阻；视觉 EPs 在伴有脑积水的情况下特别有用，可用于评估后视觉通路和视觉皮质的完整性。在脊髓栓系中，神经传导研究和体感诱发电位（SEPs）都可用于评估腰骶神经根和神经以及脊髓的运动和感觉功能，因为它们能够检测沿感觉和运动通路的亚临床传导障碍。最后但同样重要的是，神经生理学技术在手术中非常有用；通过肌电图和直接神经刺激和记录进行术中监测（IOM）能够早期检测到神经损伤，最大限度地减少神经损伤，并优化手术技术。对于不完全切除脂肪瘤和/或持续拴系的手术患儿，SEP 和 BAEP 的记录可用于证明由于躯体生长导致脊髓拴系增加，上行感觉通路的传导恶化。
